Pallet

ABSTRACT

Stacked empty pallets having registering sockets in adjoining surfaces are interlocked by latch members carried by yieldable arms extending from the mid sections of the sockets and yieldably projecting from the socket of one pallet into the corresponding socket of an adjoining pallet.

United States Patent Mangold [4 1 Aug. 15, 1972 [54] PALLET 3,363,540l/l968 Cloyd et a]. l08/53 Inventor: T. I e't Rd., Erie Pa. 16506 [22]Filed: Sept. 24, 1970 [21] Appl. No.: 75,120

Related U.S. Application Data 1 [63] Continuation-impart of Ser. No.38,778, May

521 u.s.cl. ..10s/s3,'10s/5s [51 lnt.Cl ..B65d 19/38, 865d 21/00 [58]FieldofSearch ..10s/51-ss; 220/84 Primary Examiner-James T. McCallAssistant Examiner-Glenn O. Finch Attorney-Ralph Hammar socket of onepallet into the corresponding socket of w an adjoining pallet,

3 Claims, 9 Drawing Figures PATENTEDAUB l 5 I972 SHEET 1 0F 2 IN V ENTOR. WM T PATENTEDAUB 15 m2 SHEET 2 OF 2 I I! If If I! If I! F IG.8

INVENTOR FIG.5

24 flzr FIG. 6

ATTORNEY PALLET This invention is a continuation in part of applicationSer. No. 38,778 filed May 19, 1970.

This invention is an improvement on US. Pat. No. 3,363,590, simplifyingthe latch construction for interlocking empty pallets so as to hold themin stacked relation.

In the drawing,

FIG. 1 is a perspective of a stack of empty pallets,

FIG. 2 is a fragmentary bottom plan view of one of the pallets,

FIG. 3 is a section on line 3-3 of FIG. 2,

FIG. 4 is a view similar to FIG. 3 of a modification using a stripspring to urge the latch member upward,

FIG. 5 is a fragmentary view showing the manner in which the stripspring is secured to the socket,

FIG. 6 is a fragmentary end view of the groove in which the strip springis secured,

FIG. 7 is a sectional view on line 7-7 of FIG. 8 showing anothermodification,

FIG. 8 is a plan view of the outer end of the latch, and

FIG. 9 is a plan view of the inner end of the latch.

In FIG. 1 there is shown a stack of a plurality of pallets l ofgenerally rectangular shape having peripheral side and end walls 2 eachprovided with a pair of fork entry openings 4 to provide the usualfour-way entry. Each pallet has upper and lower load carrying surfaces 6and 7. The particular pallet shown is constructed in accordance with US.Pat. No. 3,307,504, incorporated by reference. As described in greaterdetail in that patent, the load carrying surfaces 6 and 7 of each palletis associated with the lattice of intersecting ribs presented edgewiseto the surfaces and providing a rigid construction which is adapted tomolding from impact resistant plastic such as polyethylene. This ismerely one of the pallets to which the present invention is applicable.

In order to hold the empty pallets in stacked relation as shown in FIG.1, at several (e.g. four) points around the periphery of the palletthere are provided sockets 8 which extend between the surfaces 6, 7. Asshown in FIGS. 1 and 2, the sockets are spaced inward from the outerwalls 2 of the pallet. Each socket comprises walls 9, l0, l1 and 12,each extending in the thickness direction between the surfaces 6, 7 andeach integral with the adjoining sections of the pallet.

At the center of one end of each of the sockets 8 is a latch member 13supported by one of the walls of the socket, for example the wall 11.The latch member has rectangular sides 14 and ends 15 at the center ofwhich is a rounded projection 16. When the pallets are stacked one ontop of the other, the latches 13 enter the sockets 8 in the adjoiningpallet. The rectangular sides 14, 15 provide abrupt shoulders forholding the pallets in alignment. The rounded projection 16 acts as acam surface which allows the pallets to slide into position as they arestacked. Once the latches have entered the sockets 8, the stack ofpallets is interlocked by the latches so that they will remain instacked relation.

The manner of making the latch members 13 is shown in FIG. 3. As molded,the latch member 13 is integral with the lower ends of arms 17, 18 ofwidth substantially equal to the length of the latch. When viewed insection, the arms 17, 18 and the associated latch 13 form a U with thelatch at the base of the U and with the amrs offset laterally from thewalls of the socket. The arm 18 is joined to the socket wall 11 by acurved section 20. There is a similar curved section 19 at the upper endof the arm 17 which has a cut or interruption 19a so that after removalfrom the mold the latch member 13 and the arms 17, 18 assume theposition generally indicated by dotted lines 13a, 17a and 18a. The arm18 with the associated. section 20 forms a yieldable support for thelatch member 13 which permits the latch member 13 to be moved laterallyand in and out of the socket so as to prevent damage to the latchmembers while the pallets are being used. For example, when the palletis supported by its lower surface 7, the latch members 13 are free toretract within the socket. While the pallets are being stacked, thelatch members 13 are free to move either laterally or inwardly. When thelatch members 13 come into alignment with a socket 8 in an adjoiningpallet, the latch members spring into engagement with the adjoiningsocket and provide a mechanical interlock which holds the pallets instacked relation but: which yields to permit removal from the stackwithout injury to the latch members or the associated parts of thepallet.

' The arms 17, 18 and the section 20 are substantially wholly within thesockets 8 and are well protected. The latch construction is adapted tomolded plastic pallets. The integral construction provides reliabilityat minimal cost.

In order to increase the speed of operation of the latch member 13, asupplemental strip spring 21 may be used. One end of the spring has anangular section 22 seatedon the inner surface 23 of the latch member.The other end of the spring has a head 23 received in a T-slot 24 moldedintegral with the wall 1. The head is provided with inclined barbs 25which dig into the bottom walls 26 of the T-slot and resist movement outof the slot. The spring may be easily installed by pushing the head 23downward into the T-slot until the lower end 22 seats on the surface 23of the latch member 13. Once pushed into place, the barbs 25 resistoutward movement and hold the spring in assembled relation. The springsupplements the inherent resilience of the arm 18 of the latch memberand in addition overcomes any tendency of the arm 18 to take a set ifheld in its retracted position for a long period of time.

The T-slot 24 which may be molded integral with the pallet provides asimple construction for fixing one end of the supplemental spring to thepallet with minimal material and assembly cost.

In the modification of FIGS. 7-9, where corresponding parts of thepallet are indicated by the samev reference numerals, the stationarypart 27 of the latch comprises a cross wall or partition integral withthe socket walls 9, 10, 11 and 12 and having at its center an integraltubular guide 28, preferably of square or other non circular crosssection. The movable part 29 of the latch is slidable in the socket 8and has outwardly projecting ribs 30 slidably engaging the socket walls9, 10, 11 and 12. On its under side the latch member has a hollow post31 slidable in the guide member 28. At the inner end of the post 31 area plurality of resilient fingers 32 having outwardly projecting hook orlocking projections 33 cooperating with the inner end of the guide 28 tolimit the outward movement of the latch member. Spring means such as acoil spring 34 arranged between the latch member 29 and a suitable partof the stationary member 27 urges the latch member outward so that inthe extended position shown in FIG. 7 the hook members 33 stop againstthe inner end of the guide 28. When the latch member 29 projectsdownward, as shown, gravity would provide equivalent spring action. Thecoil spring 34 permits operation with the latch member 29 extendingupward. The latch member 29 and the spring 34 are separatelymanufactured parts. In the assembly, the spring 34 is assembled on thepost 31 and the assembly is pushed into the guide 28 until the hookmembers or projections 33 move past the inner end of the guide 28. Uponreaching this position, the hook members 33 spring outwardly and holdthe latch member 29 in assembled relation to the stationary latch part27.

The latch member 29 has abrupt surfaces 35 which when received in theopen end of one of the sockets 8 of an adjacent pallet cooperate withthe walls 9, 10, l1 and 12 of that socket and hold the pallets inaligned relation. Because the locking surfaces 35 resist relativemovement in all directions, only two latches per pallet are needed toprovide positive alignment in the stack. The latch members 29 also havefour inclined surfaces 36 which act as cam surfaces to assist in leadingthe I latch members into the sockets so as to assist in bringing apallet being stacked into alignment with the other pallets in the stack.The cam surfaces 36 also assist in camming the latch members inward.

The reference to upper and lower load carrying surfaces of the palletrefers to the position of the surfaces in the particular stack. Thestack could be inverted without changing the operation. The terms upperand lower are, accordingly, interchangeable and not words of limitation.

What is claimed is:

1. In a molded plastic pallet having vertically spaced load carryingsurfaces and means providing sockets extending in the thicknessdirection between said surfaces with open ends presented to saidsurfaces and registering with the open ends of sockets of adjoiningpallets in a stack of pallets of like construction, said sockets havingplastic walls extending in the thickness direction inward from saidsurfaces, latch means having a stationary part comprising a cross wallmolded integral with one of said walls inward of said surfaces andconnected by resilient means to a movable part outward of one of saidsurfaces in position to enter the open end of a socket of an adjoiningpallet of like construction, said resilient means yielding to permitretration of the movable part of the latch means into the associatedsocket.

2. The pallet of claim 1 in which the movable part of the latch has apost guided in the stationary part.

3. The pallet of claim 1 in which the resilient means is a coil springsurrounding the post and biasing the movable part outward of the socket.

1. In a molded plastic pallet having vertically spaced load carryingsurfaces and means providing sockets extending in the thicknessdirection between said surfaces with open ends presented to saidsurfaces and registering with the open ends of sockets of adjoiningpallets in a stack of pallets of like construction, said sockets havingplastic walls extending in the thickness direction inward from saidsurfaces, latch means having a stationary part comprising a cross wallmolded integral with one of said walls inward of said surfaces andconnected by resilient means to a movable part outward of one of saidsurfaces in position to enter the open end of a socket of an adjoiningpallet of like construction, said resilient means yielding to permitretration of the movable part of the latch means into the associatedsocket.
 2. The pallet of claim 1 in which the movable part of the latchhas a post guided in the stationary part.
 3. The pallet of claim 1 inwhich the resilient means is a coil spring surrounding the post andbiasing the movable part outward of the socket.